[AMDGPU] const-fold imm operands of amdgcn_update_dpp intrinsic (#71139)

Operands of `__builtin_amdgcn_update_dpp` need to evaluate to constant
to match the intrinsic requirements.

Fixes: SWDEV-426822, SWDEV-431138
---------

Authored-by: Pravin Jagtap <Pravin.Jagtap@amd.com>